Starting apparatus



Jan. 1 1963 J. E. ANTONIDIS ETAL STARTING APPARATUS Filed Jan. 25, 1960'I United States Patent Ofilice 3,071,013 Patented Jan. 1, 1963 3,071,013STARTING APPARATUS John E. Antonidis and William C. Edmundson, Anderson,Ind, assignors to General Motors Corporation, Detroit, Mich, acorporation of Delaware Filed Jan. 25, 1960, Ser. No. 4,474 4 Claims.(Cl. 74--7) This invention relates to a starting apparatus for crankingan internal combustion engine.

One of the objects of this invention is to provide a starting apparatusfor cranking an outboard engine or the like, which is economical tomanufacture and durable in operation.

A further object of this invention is to provide a starter drive thatincludes a shaft having an integral threaded portion extending along apart of its length and a smooth reduced portion, the juncture of thethreaded portion and smooth portion forming a stop shoulder for a pinionassembly that is threaded onto the threaded portion and which has a partslidably engaging the smooth portion of the shaft.

Still another object of this invention is to provide a starter apparatusincluding an electric motor having a shaft, one end of which issupported by a spherical hearing, the shaft carrying a pinion assemblywhich at times becomes meshed with the ring gear of an engine to becranked.

Another object of this invention is to provide a starting apparatusincluding an electric motor having a shaft which is supported by spacedbearings that permit slight tilting movement of the shaft, the shaftcarrying a pinion assembly at one end thereof.

A further object of this invention is to provide a bearing for the shaftof an electric starting motor or the like that includes a porous metalbushing engaging a length of the motor shaft which is crown ground tohave a central fixed diameter section that tapers off in oppositedirections toward reduced diameter sections.

Further objects and advantages of the present invention will be apparentfrom the (following description, reference being bad to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

FIGURE 1 is a sectional view of a starting apparatus made in accordancewith this invention.

FIGURE 2 is a view of a portion of FIGURE 1 showing the pinion of thestarting apparatus of this invention in mesh with a ring gear to becranked.

Referring now to the drawings and more particularly to FIGURE 1, thestarting apparatus of this invention includes an electric motor having ahousing and end frames 12 and 14. The housing contains the usualarmature 16 having an armature shaft designated in its entirety byreference numeral 18. One or more through bolts 20 are provided whichhold the end frames 12 and 14 in fixed relationship with the main frame10. The motor has field windings 21 and 22 positioned as shown inFIGURE 1. The armature 16 has the usual coil windings connected with acommutator 24 that is carried by the armature shaft.

The armature shaft 18 has a portion 26 located adjacent the commutator24 that is fitted within a bearing member 28. The bearing member 28 hasa spherical outer contour engaging arcuately extending portions 30 and32 of the end frame 14. A plate member 34 extends between the end frame14 and the bearing member 28 and has arcualte portions engaging thebearing member 28. A plate member 36 is positioned between the end frame14 and a ball 38. It is seen that the ball is opposite ends. The taperaway from the center section is arcuate and has been greatly exaggeratedin the drawings. In practice, the section 42 is ground slightly so thatthe shaft taper-s toward reduced sections from a larger diameter centralsection. It is seen that the crown ground portion 42 of the shaftengages a porous metal bearing 44 which is located in the end frame 12.

The shaft 18 has an integral threaded portion 46 and a smooth reducedportion 48. It is seen that the junction of the threaded portion 46 andthe smooth portion 48 form a shoulder 50 which operates as a stop forthe pinion assembly in a manner to be more fully described hereinafter.

The pinion assembly of this invention includes a nut member 52 having aninternal threaded portion which engages the integral threaded portion 46of the shaft 18. The pinion assembly further includes a Washer member 54that is brazed or otherwise secured to the nut member 52. and which hasportions positioned within longitudinally extending slots 56 formed in ashell member 58. The shell member 58 is :brazed or otherwise secured toa pinion member 60 having teeth which are adapted to engage a ring gear62 of an internal combustion engine to be cranked. An annular member 64formed of rubber or other elastomeric material is positioned between thewasher 54 and one Wall of the shell member 58. A snap ring 66 holds theassembly together and a thin washer 68 is positioned between the annularrubber member 64 and the washer 54. The Washer member 54 has one or moreopenings 70 which receive one end of a torsion spring 72. The spring maybe passed through one of the openings and then bent to provide apositive connection between one end of the spring and the pinionassembly. The opposite end of the spring is fixed to the shaft 18 as at74 so that the torsion spring tends to pull the pinion assembly to theposition illustrated in FIGURE 1 wherein a portion of the pinion member76 engages the wall 50 formed by the threaded portion 46 and the reduced portion 48 of the shaft.

The smooth portion of the armature shaft 18 carries a pinion stop whichincludes a snap ring 77 fitted Within a groove '78 formed in the shaft.An annular member 88 has an internal groove which receives the snap ring77 and this annular member serves as a stop for the pinion assembly whenit is thrown into mesh with the ring gear 62.

In operation of the starter drive, when the motor is energized to causea rotation of the shaft 18, the pinion assembly moves rightwardly inFIGURE 1 to the position of FIGURE 2 Where is becomes meshed with thering gear 62. The pinion assembly moves rightwardly due to the fact thatthe shaft initially rotates much faster than the pinion assembly so thatit is moved along the shaft by the engagement of the threaded portion 46with the internal threads of nut member 52. The nut member, of course,drives the washer 54 which, in turn, drives the shell member 58 and thepinion member 60. It is seen that the pinion member 60 slides on thesmooth portion 48 during the time that it is moving to a meshed positionand during the time that it is returning from its meshed position. Oncethe engine starts, the pinion as sembly is driven faster than the shaft48 is rotating and it therefore moves lefitwardly along the threadedportion 46 of the shaft to the FIGURE 1 position. The pinion assembly isat all times biased towards its FIGURE 1 position by the torsion spring72 which is connected between the pinion assembly and the shaft. Theshoulder L fi 50 engaging portion 76 of the pinion provides a stop forthe pinion during its leftward movement.

The provision of the crown ground portion 42 of the shaft assures thatthe porous metal bearing 44 will not be scored or otherwise injuredduring operation of the starting -apparatus. This is true because theshaft may tilt to some minor extent without causing a scoring orroughening of the porous metal bearing 44. The bearing assembly whichincludes the bearing member 28 also permits the armature shaft 18 totilt to some extent during the operation of the starting apparatus.Thus, the bearing member 23 has universal movement with respect to theend frame 14 and the ball 38 takes up the end thrust applied to theshaft 18 during meshing of the pinion 60 with the ring gear 62. It is tobe pointed out that when end tooth abutment occurs between the pinion 60and the ring gear 62, the member 64 is compressed and thrust to the leftin FXGURE 1 is set up. The ball 38 absorbs the thrust and allows theabutment to be cleared by providing low frictional drag to the rotationof shaft 26 as compared to other types of bearings. It has been foundthat the bearing apparatus of this invention provides for good meshingand unmeshin-g performance and also provides for long life of the partsof the starting apparatus.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. Engine cranking apparatus comprising, an electric motor having firstand second end frames, a shaft carrying the armature of said electricmotor and journalled in first and second bearings supported respectivelyin said first and second end frames, said shaft having a first portionextending beyond said first end frame, said first bearing being a plainmetal bearing having an inner annular surface of uniform diameter, saidshaft having a crown ground portion fitting in said first bearing anddirectly engaging the inner annular surface of said first bearing, saidfirst portion of said shaft that extends beyond said first end framehaving a breaded section formed with integral threads and a smalldiameter section of uniform dameter, said smaller diameter section andsaid threaded section having a junction which forms an annular stopshoulder, a unitary pinion member having a central bore slidablyengaging the smaller diameter section of said shaft and having anannular section which is directly engage-able with said stop shoulder inone position of said pinion member, a generally cup-shaped shell membersecured to said pinion member, and nut means engageable with saidthreaded section of said shaft for driving said shell member, said nutmeans, shell member and pinion member being shifted to a crankingposition solely by rotation of said shaft when said motor is energized.

2. Engine cranking apparatus according to claim 1 wherein an annularmember formed of elastomeric material is positioned between said shellmember and nut means.

3. Engine cranking apparatus according to claim 1 wherein a torsionspring is connected between the shaft and the nut means to urge theannular section of the pinion member toward the stop shoulder.

4. Engine cranking apparatus according to claim 1 wherein the secondbearing includes a spherical thrust bearing.

References Cited in the file of this patent UNITED STATES PATENTS1,390,077 Bijur Sept. 6, 1921 2,228,394 Marvin et al. Ian. 14, 19412,423,063 Buxton June 24, 1947 2,813,762 Bridenbaough Nov. 19, 19572,833,701 Kuhagen June 10, 1958 2,944,427 Antonidis et al. July 12, 19602,944,428 Antonidis et a1. July 12, 1960 FOREIGN PATENTS 837,530 GreatBritain June 15, 1960

1. ENGINE CRANKING APPARATUS COMPRISING, AN ELECTRIC MOTOR HAVING FIRSTAND SECOND END FRAMES, A SHAFT CARRYING THE ARMATURE OF SAID ELECTRICMOTOR AND JOURNALLED IN FIRST AND SECOND BEARINGS SUPPORTED RESPECTIVELYIN SAID FIRST AND SECOND BEARINGS SUPPORTED RESPECTIVELY IN SAID FIRSTAND SECOND END FRAMES, SAID SHAFT HAVING A FIRST PORTION EXTENDINGBEYOND SAID FIRST END FRAME, SAID FIRST BEARING BEING A PLAIN METALBEARING HAVING AN INNER ANNULAR SURFACE OF UNIFORM DIAMETER, SAID SHAFTHAVING A CROWN GROUND PORTION FITTING IN SAID FIRST BEARING AND DIRECTLYENGAGING THE INNER ANNULAR SURFACE OF SAID FIRST BEARING, SAID FIRSTPORTION OF SAID SHAFT THAT EXTENDS BEYOND SAID FIRST END FRAME HAVING ATHREADED SECTION FORMED WITH INTEGRAL THREADS AND A SMALL DIAMETERSECTION OF UNIFORM DAMETER, SAID SMALLER DIAMETER SECTION AND SAIDTHREADED SECTION HAVING A JUNCTION WHICH FORMS AN ANNULAR STOP SHOULDER,A UNITARY PINION MEMBER HAVING A CENTRAL BORE SLIDABLY ENGAGING THESMALLER DIAMETER SECTION OF SAID PINION MEMBER, A GENERALLY CUP-SHAPEDSHELL MEMBER SECURED TO SAID PINION MEMBER, AND NUT MEANS ENGAGEABLEWITH SAID THREADED SECTION OF SAID SHAFT FOR DRIVING SAID SHELL MEMBER,SAID NUT MEANS, SHELL MEMBER AND PINION MEMBER BEING SHIFTED TO ACRANKING POSITION SOLELY BY ROTATION OF SAID SHAFT WHEN SAID MOTOR ISENERGIZED